1. Field of Invention
The invention relates to torque calibration techniques and more particularly to a method of obtaining same wrench torque by calibration by testing different force exertion points on hand grip of an electronic torque wrench and an electronic torque wrench therefore.
2. Description of Related Art
Wrench is a tool used to provide grip and mechanical advantage in applying torque to turn objects (e.g., rotary fasteners such as nuts and bolts).
As sufficient torque is applied to the head of a fastener, the fastener is secured. However, it is also that overstressed fasteners can be broken whereas under-stressed fasteners can lead to joint failure, leakage, etc. Thus, indication of torque exerted on a workpiece (e.g., precise mechanism, medical tool, etc.) by a wrench by means of a digital display is desirable.
A great array of electronic torque wrenches for satisfying above need is commercially available. Typically, exerted torque indicated in the form of digits can be shown on a display of the wrench in use. However, it is found that different torques are applied to a workpiece when the gripping positions of the hand grip of a torque wrench are different. That is, there is an error between the preset torque value and actual one. It is undesired for such workpieces (e.g., precise mechanism, medical tool, etc.) if the error is greater than the maximum error since high precision is always desired. Thus, the need for improvement still exists.